1. Field of the Invention
The invention relates to nonaqueous batteries; in particular, to sodium-sulfur batteries.
2. Description of the Prior Art
Sodium-sulfur batteries have certain advantageous characteristics which make them attractive for many commercial applications. For example, they have particularly high energy densities, often in the range of 200 watt-hours per kilogram, and also high power densities. Sodium-sulfur batteries also have particularly high efficiencies and long life times. In addition, sodium-sulfur batteries are inherently inexpensive to make because of the low cost of the materials required for manufacture.
Conventional sodium-sulfur batteries must be operated in the temperature range between 300.degree. and 400.degree. C to prevent solidification of discharge products on the solid electrolyte. Reduction of this operating temperature without significant deleterious effect on operating characteristics would make sodium-sulfur batteries more attractive for many commercial applications.